1. Field of the Invention
The present invention relates to a liquid-phase growth apparatus for growing a crystal on a seed substrate that is vertically held with a substrate holder and is dipped in a solution containing a solute (raw material) for forming the crystal in a crucible, and to a liquid-phase crystal growth method using the apparatus.
2. Description of the Related Art
Liquid-phase growing is known as a method for preparing a high-quality monocrystalline thin film at relatively low temperature. Unfortunately, in a dipping process that includes dipping a substrate held with a substrate holder in a solution, films are deposited on two faces of the substrate.
Some methods are proposed for depositing a thin film only on one face of the substrate. For example, a substrate is placed on a platinum holder and fixed with fixing claws to inhibit growth of the film on the rear face of the substrate. In another proposed method, two substrates that are in close contact with each other at the rear faces are dipped in a solution to facilitate crystal growth on the front faces of the substrates.
In liquid-phase crystal growth by general dipping, the substrate is held to the substrate holder horizontally or at a slight tilt angle from the level line. In such a case, a thicker film is deposited on the down face of the substrate rather than the upper face. In particular, this tendency is noticeable in liquid-phase growth of a silicon crystal from an indium solvent since the specific gravity of the material (silicon) for forming the crystal is considerably lower than that of the solvent.
When the substrate is vertically held in a general dipping method, films may be formed on two faces of the substrate or the substrate may be cracked by thermal expansion.